The Four Dimensions of the Universe

It's like the difference between a globe or sphere has positive curvature and that if you go out in to perpendicular directions, you'll eventually get a bit closer. If we find that it's not flat, that would be very interesting and it gives us insight into the early evolution of the universe and possible late evolution of it. So as far as we can tell by looking at the shape of the universe, it's very close to flat and could plausibly be flat, but we don't know for sure.